1. Field of the Invention
The present invention relates to a method for producing a semiconductor optical device.
2. Description of the Related Art
Non-Patent Document 1 (S. Y. Chou, P. R. Krauss and P. J. Penstrom, Applied Physics Letters, vol. 67 (1995) pp. 3114-3116) describes a nano-imprint technique. Specifically, a poly methylmethacrylate (PMMA) resin is coated on a silicon substrate and the resultant PMMA resin is heated to the glass transition temperature (105° C.) of the PMMA resin or higher. The heated PMMA resin is pressed with a quartz mold on which a predetermined pattern has been formed. After the PMMA resin and the quartz mold are cooled, the PMMA resin is removed from the quartz mold. Thus, as a result of the transfer of the pattern of the quartz mold to the PMMA resin, the patterned PMMA resin is provided. The silicon substrate is etched by using the patterned PMMA resin as an etching mask. For example, such a pattern includes cylindrical portions having a diameter of 25 nm and a depth of 100 nm.